1. Field of the Invention
This invention relates generally to systems and methods for sensing types of liquids passing through a line or stored in fuel tanks and other containers. More particularly, the present invention relates to sensing the constituents of fuel in a Flexible Fuel Vehicle by propagating electromagnetic waves into a liquid container or fuel line. Particular embodiments of the present invention detect fuel composition and alcohol content in a fuel line of a Flex Fuel Vehicle.
2. Description of the Prior Art
Flex Fuel Vehicles (FFVs) are motor vehicles which are compatible with the use of alcohol as a significant constituent of the vehicle's fuel. Alcohol based fuels are an alternative type of renewable, transportation fuel made from bio-material, potentially reducing dependence on petroleum based fuels. A motorist may advantageously gain increased horsepower for better engine performance because alcohol based fuels typically have a higher octane rating than premium gasoline. Alcohol based fuels include “E85,” a term for motor fuel blends of 85 percent ethanol and 15 percent gasoline. E85 is an alternative fuel as defined by the U.S. Department of Energy and is intended for use in FFVs. Ethanol and other alcohols burn cleaner than gasoline and is a renewable, domestic, environmentally friendly fuel. FFVs can typically be fueled on any blend of ethanol and gasoline, from 0% ethanol and 100% gasoline up to 85% ethanol and 15% gasoline (E85).
It is important for the Engine Management System (EMS) of an FFV to have information on the composition of the fuel, so that the EMS may adjust certain vehicle parameters to optimize vehicle performance, specifically fuel consumption, emissions control and engine power.
Motor vehicle operators generally rely on indirect methods of determining the amount of alcohol in an FFV's fuel tank. The most common method of establishing the alcohol content of the fuel remaining in a motor vehicle is to use software algorithms implemented in the Body Controller Module or EMS of the vehicle. Alcohol content of the fuel may be altered by the driver at each filling of the fuel tank as there is no requirement to continuously use E85 fuel or conventional gasoline. Algorithm-based systems are slow to react to changes in the fuel composition and are typically only accurate to plus or minus ten percent alcohol content. Furthermore, such systems are even more ineffective when employed in a motor vehicle with saddle fuel tanks or similar fuel storage arrangements where the fuel may not be uniformly mixed or where the fuel mixture might change over time as the vehicle is driven.
Direct measurement systems exist, but require installation of a mechanism inside, or in-line with, the fuel line. Repair, replacement, or adjustment of such an internal or in-line fuel composition measurement mechanism is problematic.
The prior art fails to provide a reliable, inexpensive, and accurate system and method of measuring the composition of fuel in a motor vehicle using a system that can be installed external to a fuel line, fuel tank, or the like.